Objective: To compare the efficacy and safety as well as associated image quality of catheter-directed CT angiography (CCTA) with a low dose of iodine contrast agent compared to intravenous CTA in patients undergoing endovascular aortic aneurysm repair (EVAR).
Methods: Retrospective data analysis of 92 patients undergoing EVAR between January 2009 and December 2017 was performed. Patients were divided in two groups; those receiving CTA (n = 59) after intravenous contrast agent application and those receiving CCTA (n = 33) via an intraarterial catheter placed in the descending aorta. Demographic and cardiovascular risk factors as well as renal function parameters before, immediately after and 6-60 months after EVAR were evaluated. As primary endpoint, changes in serum creatinine levels in the two groups were evaluated. Secondary endpoints encompassed complications associated with intraarterial catheter placement. Objective (signal-to-noise ratios) and subjective image quality (5-point Likert scale) were compared.
Results: Amount of contrast medium was significantly lower in CCTA compared to i.v. CTA (23 ± 7 ml vs. 119 ± 15 ml, p<0.0001). Patients undergoing catheter-directed CTA had higher baseline creatinine values compared to the group with intravenous iodine application (1.9 ± 0.6 mg/dl vs. 1.3 ± 0.5 mg/dl; p<0.0001). Follow-up serum creatinine levels however did not show significant alterations between the two groups (1.9 ± 0.4 mg/dl vs. 1.3 ± 0.5 mg/dl). No major complications were detected in the CCTA group. Signal-to-noise ratio (SNR) was comparable between i.v. CTA and CCTA (8.5 ± 4.6 vs. 7.7 ± 4.0; p = 0.37) and subjective image similarly revealed no differences with a good interobserver agreement (ICC = 0.647).
Conclusions: Catheter-directed CTA is safe and provides comparable image quality with a substantial retrenchment of the needed amount of iodine-based contrast medium. However, no benefit of the reduced contrast medium protocol with respect to renal function was observed.